The present invention relates to oval shaped discharge pipes particularly adapted to be used for the discharge of drainage or sewerage.
It is considered desirable to use a synthetic resin pipe having an oval cross sectional shape, such as ellipsoidal or one similar thereto, instead of a more conventional round synthetic resin pipe having true circular cross section to discharge water or sewage. The advantage of an oval shaped pipe over a round pipe of similar cross sectional area, is that the oval pipe, if laid with the longest cross sectional dimension perpendicular to the horizontal, will have a larger depth of water therein at low water periods. This allows the water to maintain a considerable speed and prevents the accumulation of solid filth or sedimentation. Accordingly the oval internal shape of such pipes makes them particularly useful for drainage or sewerage pipes. However, the external cross sectional shape of the pipes is also oval and that causes numerous difficulties in the instaloation of such pipes. For example, to achieve the benefit of the oval internal cross section, it is necessary to lay the pipes underground with their longitudinal axes directed vertically, but it is difficult to lay the pipes with their longitudinal axes directed precisely vertical. Moreover, if they were initially laid down with their longitudinal axes precisely vertical, they would require additional supports to keep the pipes in the desired position since they lack stability.